The use of a flexible drill assembly for operating in the coal mining industry is relatively new. The flexible drill provides a compact drill unit which can be installed in locations having very little space. Such drill shaft may be much shorter than the height of a man, and the drill string which consists of a series of interconnected drill sections or links is contained in a flexible guide tube which can be easily stored. The use of this type of drill string makes it possible to use a solid drill shaft of much greater length than the height of the mine shaft. One characteristic of this type of drill string is that each drill section consists of a ball and socket or universal type of connection which is articulated when the drill is rotated in one direction such that it can move over a limited angular range, and when the drill is turned in the opposite direction the drill sections lock together to create a straight solid shaft. When the drill has been in operation for some time, the drill sections tend to lock together rather tightly, and there is some concern that on withdrawal of the drill shaft, even with some sections reversed, torque applied may fail to release from each other, thereby tending to damage or score up the curved flexible guide tube through which the sections are conveyed to transfer them from vertical to horizontal storage.